Fifting magnet



June 26, 1923. 1,459,830

F. W. JESSOP v LFTING MAGNET Filed April 29, 1918 2 Sheets-Sheet 1 Patented June 26, 1923.

PATENT OFFICE.

UNITED STA-TES FRANCIS W. JESSOP, OFCLEVELAND, OHIO, ASSIGNOR T0 THE OHIO ELECTRIC & CON- TROLLER COMPANY, OF CLEVELAND, OHIO, A CORPORATION 0F OHIO.

LIFTING MAGNET.

Application filed April 29, 1918. Serial No. 231,565.

T o all whom 'it may concern.:

Be it known that I, FRANCIS lV. Jnssor, a citizen of the United States, residing at Cleveland. in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Lifting Magnets, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to improvements in the construction of lifting magnets, and has for its main objects the production of a very substantial and durable st-ructure that will withstand the hard service to which lifting magnets are subjected; which will not be affected by the relements when exposed to the weather; and the electrical connections whereof are preferably ofa permanent nay ture so as to be practically unbreakable from the shocks and jars incident to the use of the apparatus.

In other words, the invention may be said to have as its fundamental purpose the production ofa lifting magnet that is practically indestructible from customary use and which requires no attention except for operating it.

To the attainment of these objects, I may construct the magnet of a very heavy annular pole shoe constituting the coil casing and a heavy central pole piece, that are connected together and maintained in concentric relation to each other by a massive cover; the latter being attached to the annular pole shoe by securing means, such as screws, that are protected by portions of the cover; and to the central pole piece preferably by means`of a heavy stud. It is desirable to provide the cover and the pole parts with intercngaging portions which serve to hold said parts and cover aga-inst any relative lateral movement, so that the securing means between the cover and pole parts are relieved of all but tensional strains. Because of this construction there is no danger of shearing the. securing means as a result of a side blow of the magneto against a mass of material to be handled, or other obstruction. The coil terminals and leads are preferably brazed together to insure them against becoming severed or loosened from shocks or jars. The coil terminals are also preferably constituted so as to permit them to yield slightly in response to and accordingly absorb somewhat the shocks and jars, thus avoiding fracture.

More limited objects of the invention are to provide a peculiar design of cover that will drain readily of water; which is 'provided with protective elements for the securing means between the cover and pole parts; and which has formed integral with it a substantial terminal box or encasement for the electrical connections between the coil terminals and leads and access to the interior of which may be readily gained for the purpose of making the connections, and which is effectively closed by simple means convenient of manipulation.

A further object of the present invention, and one which is not necessarily limited to incorporation in a lifting magnet although peculiarly adapted thereto, is the provision of a simplified yet very effectual method of insulating from each other the several spiral sections of the magnet winding.

The foregoing objects and others which will become apparent as this description proceeds are attained in the construction illustrated in the drawings accompanying and forming a part hereof and wherein Fig. l is a partial plan view of my improved magnet; Fig. 2 is a section substantially on the line 2 2 of Fig. l; Fig. 3 is a perspective view of the magnet coil with a portion broken away to reveal certain structural details; and Fig. 4 is a similar view of some of the elements, in separated condition, of which one of the coil insulating layers is composed. j

Taking up a detailed description of the invention by the use of reference'characters, 1 is an annular pole shoe and ,2 a central `pole piece 'that are connected together and maintained in concentric relation to each other through a cover 3. Connection is made in the present instance between the central pole piece and cover by means of a stud 5 that is embedded withintlie pole piece preferably at the time the latter is cast, and which projects upward through a central aperture of the cover and has applied to its threaded upper end a nut 6' that, after being drawn down tightly, may be held against turning by ardowel 8, shown in the form of a screw. Ca screws 10 connect the peripheral portion o the cover'with the annular pole shoe 1, and are shown as held against turning by split washers 11 that are inserted between the heads of the screws and the adjacent surface of the cover. The top outer edge portion of the pole shoe 1 is rabbeted to receive the peripheral depending flange 12 of the cover; and the upper end of the central pole Jpiece 2 is provided with a shallow recess 14 Within which tits a projection 15 of the cover. Thus the cover and pole parts are securely heldagainst lateral relative movement independent of the foregoing securing means consisting of the stud 5 and screws 10. l

It will be observed that the cover is formed with a heavy annular bead 16 which-sur rounds and is higher than the stud 5 and thus securely protects it; and the depressed portion enclosed by the bead is preferably partially iilled wlth a suitable weatherproof sealing material 17, such as asphaltum or the like, to thoroughly close the interstices between the nut and cover to the eX- clusion of water or other deteriorating elements. The top surface of the cover from the crest of the bead 16 outward is generally inclined downward to within a short distance of its edge where it rises abruptly to form an annular bead 18 which is divided into short segmental sections by drain notches 1'9 adjacent the screws 10 so that any Water deposited upon the cover may escape through these notches. Attention is also called to the fact that beneath the head of each screw 10 the surface of the cover is slightly elevated to facilitate draining in the immediate vicinity of the screws 1() and washers 11. The bead 18 is high enough to thoroughly protect the screws 10 from any blows which may be imposed upon the magnet in the course of its use, and radial ribs 21 extend inward from the bead 18 and merge into the'cover at the base of the bead 16. These ribs also serve to protect the screws 10, and they have a further function of dissipating radiating heat and thus abstraeting it from the interior of the magnet.

Pairs of lugs 25 are equally spaced about the cover, and are shown as radiating from the center thereof; and passing through thc lugs of each pair is a pin 26 to which may be connected the lewer link of one of the branches 27 of a suspension element or chain through which the magnet is raised and lowered and swung from place to place in the performance of its works all of which is common to apparatus of this character and will therefore` be readily understood by those acquainted with the art.

As previously mentioned the annular poley shoe 1 constitutes the magnet casing; and near its lower end is extended inward to provide a shoulder 30, lopposed to and in substantially the plane of a shoulder 31 that is formed by enlarging the lower end of the central pole piece 2. An annular coil protecting plate 33 rests upon the shoulders 30 and 31 and has formed, on its outer face, a

series of radial strengthening and heat disspirals- 36 of copper ribbons or the like, the

convolutions whereof are insulated from each other by any suitable material; and the spirals are -separated by layers 38 of insulating material, each layer preferably being constituted of two pliesof sheet asbestos impregnated with a moisture excluding substance, having within itself, insulating prop erties, each ply being formed of segments, preferably 3 in number, as indicated -in Fig. 4, the joints between the segments of each ply being offset, or broken so to speak, with those of the other so that adjacent coils are very eifectually insulated from each other. The inner 'edges of the layers 38 are embedded within a sleeve 44 of material similar to that ,whereof the layers are made; and the outer edges of the layers are separated by inserts 45 of similar material. A metallic collar 46 is inserted within the sleeve 44, and strips 47 of metal have their inner ends secured to the collar 46 as by screws 48. These strips, with metallic bands 49, constitute clamps for binding the elements of the coil securely to ether. The bands 49 have their inner en s secured to the lower edge of the collar 46, as by screws 50, and pass outward beneath the coil and upward where their outer ends lie flat against the underneath side of the projecting ends of the corresponding strips 47. When the coil is placed within the casing the inner ends of the strips 47 bear upon the top of the central pole piece 2, and are shown as secured thereto by scrws 52. Long screws 53, extending through apertures 1n the outer ends of the stirps 47 and bands 49, are threaded into the inwardly extending lower portion of the pole shoe 1. The underneath surface of the cover 3 is grooved at 55 for the aecommodation of each of the strips 47.

The several spirals of the coil are connected according to prevailing practice and thus organized into a continuous winding, and 'the ribbons or elements of the upper and lower spirals are led upward, one to each of two bores or cavities 60 that are formed in a heavy oblong boss 61 which rises from the cover, the ends of the windings constituting the terminals 62 and 63 of the coil. The upper end of each bore or cavity 60, is internally threaded for the reception of a plug 64 which serves as a convenient closure for the terminal cavity. Each cavity may be lined with a sleeve 65 of insulating material and inside the sleeve are deposited a stack of insulating washers 67, the apertures of the washers registering to produce a recess for the coil terminal, that is closed at its upper end by disks 68 of insulating material. A passage 70 leads through the side of the boss 6l into each of the terminal cavities 60, and the end of a flexible armored cable 7 3 is inserted through each of the passages and is held permanently therein by a deposit of suitable material, such as babbitt, that is poured into the passage. The inner end of a lead 74, entering through the flexible cable,

is wrapped about and preferably brazed to the coil terminal so that the connection is made permanent and capable of withstanding any shocks or jars imparted to the magnet in its use. It will be observed that the upper end of the boss 61 is sufficiently depressed to leave a surrounding rib that will protect the plugs 64; and the depressed portion may be drained through a groove in the side of the boss.

The pole piece 2 has a circumferential groove 76 immediately above the shoulder 31, and vertical grooves 77 lead downward from the upper end -of the pole piece to the circumferential groove. A. suitable sealing substance 78, preferably asphaltum compound, is poured into the casing and fills the joints between the coil protecting plate 33 and the shoulders 30 and 31, the substance flowing down the grooves 77 and about the groove 76 so that it is thoroughly distributed about the inner joint.

An important feature of my improved construction and one possessing marked advantages over the corresponding feature of prevailing types of lifting magnets, is the locating of the means connecting the parts of the coil enclosing casing (in the present instance, said means consisting of the screws l0) at the end of thecasing remote from the working face of the magnet. in all lifting magnets of the class towhich my improvements relate and with which l am familiar, the connecting means are situated in close proximity to the working face where they are exposed to very hard treatment and heavy blows, making it necessary to replace them frequently. According to my arrangement, the connecting means are beyond the reach of any objects into'contact with which the magnet is swung in its customary use.

A further important distinction of my invention is the employment of a comparatively heavy outer pole shoe which constitutes the coil casing. Heretofore, the outer pole shoes of lifting magnets `have been of insufficient cross-section to withstand the test of service and wouldrbreak easily when swung vigorously against or dropped upon objects to be handled, requiring frequent removal. This difficulty is entirely eliminated by my design,y

Having thus described my invention, what I claim is :-q

l. In a lifting magnet, the combination of an annular casing for the coil, said casing constituting a pole shoe, a circular pole situated centrally of the casing and having its upper end in substantially the plane of the corresponding end of the casing, a cover having a substantially flat inner surface applied to the pole piece and casing, the pole piece being provided with a central, threaded stud and the cover with an aperture through which the stud projects, a nut applied to said stud beyond the cover, fastening means extending through the edge poi'- tion .of the cover and embedded in and thus protected by the casing, and a coil within the casing and surrounding the pole piece.

2. In a lifting magnet, the combination of a casing for the coil consisting of an annular coil protecting wall and constituting a pole shoe, a pole piece, a cover for application to the casing and pole piece and by means of which said parts are properly positioned with respect to each other, means disposed within the diameter of the casing wall and connecting the cover to said wall and pole piece, the cover having protecting parts for shielding the connecting means, and a coil within the casing about the pole piece.

3. In a lifting magnet, the combination of a coil enclosing casing, said casing constituting a pole shoe and having an inwardly extending shoulder adjacent its lower end, a pole pieceV situated within the casing and having its upper end in substantially the plane of the upper end of the casing, a cover havinga substantially flat. under-surface applied to the casing and pole piece and through which they are connected and maintained in proper position with respect to each other, the pole piece having an outwardly extending shoulder in substantially the plane of the shoulder of the casing, a coil protecting plate sustained by said shoulders, a coil supported within the casing and surrounding the pole piece, and means connecting the cover to the casing and to the pole piece.

4. lin a lifting magnet, the combination of a casing, a pole piece maintained central thereof, a cover, means for attaching the cover to the casing and pole piece, bars bearing upon the upper end of the pole piece, lmeans for connecting said bars to the pole piece and casing, a coil clamped to said bars in the space between the pole piece and casing, vand means connecting the cover to the casing and pole piece.

'5. ln a lifting magnet, the combination of an annular casing, a pole piece sustained central thereof, a cover applied to the casing and pole piece, bars extending radially yacross the space between the'pole piece and casing and having their inner ends bearing llO upon the pole piece, means connecting the bars withl the pole piece and casing, a coil protecting plate closing the space between the pole piece and casing at the end remote from the cover, acoil within said space and clamped to the aforesaid bars and means pole shoe through which the region there- V -about may be drained, and a coils contained within the space between ythe pole shoe and pole iece. p

7 n a lifting magnet, the combination of a pole shoe constituting the coil casing, a

with a pole piece, a cover `'applied' to said pole parts, means connecting the cover and the pole piece, further means disposed within the diameter of the cover and connecting the edge portion of the cover and the pole shoe, the cover having an upwardl -extending peripheral lbead and ribs exten ing radially inward therefrom, the space Within the bead and between adjacent ribs bein inclined downward and outward, and the d having notches in the vicinity of the connecting means between the cover and pole shoe through which the region thereabout may be drained, and a coil contained within the space between the pole shoe and pole piece. 8. In a lifting magnet, the combination of a pole shoe, a pole piece, a cover applied to said pole parts, connections between the cover and the pole piece, screws extending throu h the edged portion ofthe cover and into t e pole shoe, theheads/ of said screws rotruding beyond the cover, said screws eing spaced at intervals about the circumference of the cover and inward ofthe edge thereof, the cover 'having an upwardly extendin eripheral bead and ribs extending inwar herefrom between adjacent ones of the aforesaidscrews, the surface of the cover for a distance inside the bead being inclined downwardly and'outwardly, the bead having a notch in`the vicinity of each screw through which the region thereabout may be drained, thev` surface of the cover beneath each screw head being slightly elevated, and a coil within the space between the pole s hoe and pole piece. Y

9. In a lifting magnet, the combination le shoe, a. polepfiece having a threaded stud, a, cover for application to the of a casing, a coil within the casing, the v casing having a -boss provided with a through passageway into which a terminal of the coil projects, and means closing the outer end of said passageway, the boss havin a lateral passageway through which a lea is directed for connection with the coil terminal.

ll. In a lifting magnet, the combination of inner and outer pole pieces, a cover through which said pole pieces are connected and maintained in roper spaced relation to each other, a coi within the space between the pole pieces, the cover having a boss provided with a through passageway for the accommodation of a terminal of the coil and means for closing the passagewa the boss having a lateral passageway through which a lead is directed for connection with the coil terminal.

12. In a lifting magnet, the combination of inner and4 outer pole pieces, a cover through which said pole piec/es are connected and maintained in proper spaced relation to each other, a coil within the space between the pole pieces, the cover having` a boss provided with through bores for the accommodation of the coil termina-ls, the outer ends of the bores being threaded, and threaded. plugs for closing the bores, the

,boss having lateral passageways through which leads are directed for connection with the coil terminals.

13. In a lifting'ma-gnet, the combination of inner and outer pole pieces, a cover through which said pole pieces are connected and maintained in proper spaced relation to each other, a coil within the space between the pole ieoes, a cover having a boss provided with t rough bores into which they terminals of the coil are arranged to project, a series of washers within each bore 'and in the cavity formed by the apertures of which one of the terminals reposes, a disk applied to the upper end of each series of washers for closing the cavity formedL byv their apertures, and means closing the outer end of eac-h bore, the boss having lateral passageways through which leads are directed for connection with the coil terminals.

n l 14:. In a lifting magnet, the combination of a casing, a coil within the casing, and leads extending inward through passageways of the casing and having permanent inseparable connection with the terminals of the coil.

15. A coil for electromagnets of the class set forth comprising a series of spirally wound sections superposed one above another and connected in series thereby to constitute the coil winding, and layers of insulating material interposed between adjacent sections of the winding, each layer consisting of a plurality of plies, each pl formed of sections, the joints between whic are broken with respect to the joints between the sections of the adjacent ply.

16. A coil for electromagnetsl of the class set forth comprising .a series of spirallyI wound sections superposed one above another and connected in series thereby to constitute the coil winding, and layers of insulating material interposed between adjacent sections of the Winding, each layer consisting of a plurality of plies of sheet insulating material, the plies being made up each of a number of segments the joints between which are offset with respect to the joints between the segments of the adjacent ly. p 17. In a lifting magnet, the combination of a pole shoe constituting the casing for the coil and having, adjacent its lower end, an inwardlyextending shoulder; a pole piece; a separabley cover through which said pole parts are connected and maintained in proper position with respect to each other; the pole piece having an outwardly extending shoulder to substantially the plane of the shoulder of the pole shoe and a circumferential groove above its shoulder with tributary grooves leading'thereto from the upper end of the pole pieces; a coil protecting plate sustained by said shoulders; a coil contained within the space between the inner constitutin a pole shoe, a circular pole situated centra ly of the casing and having its upper end in substantially the plane of the corresponding end of the casing, a cover having a substantially flat inner surface applied to the pole piece and casing, the pole piece being provided with a central, threaded stud and the cover with an aperture through which the stud projects, a nut applied to said stud beyond the cover, fastening means extending through the edge portion of the cover and embedded in and thus protected by the casing, and a coil within the casing and surrounding the pole piece, the casing and pole piece having parts interitting with parts of the cover to properly position the pole piece and casing with respect to the cover.

19. A coil for electro-magnets of the class set forth comprising a sleeve of insulating material having circumferential grooves, a series of spirally wound sections of conducting material superposed one above another and connected in series thereby to constitute the coil winding, and layers of insulating material interposed between adjacent sections of the winding and having their inner edges contained within the grooves of the sleeve.

20. A coil for electro-magnets of the class set forth comprising a sleeve of insulating material having circumferential grooves, a series of spirally wound sections of conductive material superposed one above another and connected in series thereby to constitute the coil winding, and layers of insulating material interposed between adjacent sections of the winding and having their inner edges contained within the grooves ofthe aforesaid sleeve, each layer j consisting of a plurality of plies, each ply formed of sections the joints between which and outer pole parts; and means connecting, are broken with respect to the joints between the cover to the pole parts, the casing being adapted to be filled with a sealing substance.

18. In a lifting magnet, the combination of an annular casing for the coil, said casing the sections of the adjacent ply.-

In testimony whereof, I hereunto aflix my signature.

FRANCIS W.I JESSOP. 

